scmutil: handle conflicting files and dirs in origbackuppath
When ui.origbackuppath is set, .orig files are stored outside of the working
copy. However conflicts can occur when files or directories end up having the
same name. These conflicts cause Mercurial to abort, even if they've been
created as a result of different backups.
Make sure we always replace files or directories in the origbackuppath if
they conflict with another file or directory.
Test Plan:
Add new unit test for conflicting paths.
Differential Revision: https://phab.mercurial-scm.org/D680
#require unix-permissions no-root
$ hg init a
$ cd a
$ echo foo > b
$ hg add b
$ hg ci -m "b"
$ chmod -w .hg/store
$ cd ..
$ hg clone a b
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ chmod +w a/.hg/store # let test clean up
$ cd b
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
$ cd ..